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YorkshireDave · Sep 18th, 2021, 20:54

My two penneth of experience regarding DEM failure.

My issues started with occasional anti skid service warnings. I then noticed fuel consumption had risen & I had no idea why.
My next sympton was a 'rumble' similar to an early wheel bearing failure but I had trouble locating it and it wasn't prevalent when turning left or right.
Eventually, over some months, more spurious messages appeared and eventually I got the brake failure message along with no tacho, speedo or water temp.

I was convinced it was the CEM (based on various tinterweb posts) so I stripped it out only to find it had already been replaced! Whilst it was great news on one level, it also chucked a huge spanner into my thought process 🤔

Having used Lukas' skills at Volvo Diagnostics a couple of years previous, he was the only person I felt I could trust to give me a definitive answer. I know from experience he does not rely entirely on the output from a computer!

His advice was simple & incisive. Disconnect the DEM & clear the codes. If the issues disappear, aside from the antiskid warning, them the DEM is the prob.

Getting to it & disconnecting it was a challenge. However, the following drive was clear of the break failure warning, the instruments worked again, the gearbox worked & the rumble noise disappeared.

I left Wetherby at 04:30 next morning for Tilbury as Lukas said he'd refurb my DEM while I waited. As someone who started working life in electronics and almost ever since been in engineering, the quality of the refurbishment was truly sublime. Even the case was cleaned to a literal 'just out of the mould' standard - truly spotless. It turned out it had the wrong firmware for my vehicle but they sorted that with batting an eyelid!

Volvo's price for a replacement & programming was £1200. Lukas' price was £140, which included his freely given priceless advice.

Before refitting I was advised to test the pump which I did. Unfortunately I don't think my Haldex has ever been serviced so that'll be done next week with a new filter & oil. I refitted today and, honestly, the difference is night & day. Gear changes are smoother than a babies bum, rumble has disappeared, fuel consumption has improved & no more messages!

My journey here was ultimately successful. However it would have been far less painful if we Volvo owners had access to some decent flow charts where simple(ish) tests, such as Lukas suggests, where we could narrow down possible causes. Anyone up for working on some?

Sep 18th, 2021, 20:54	#32
YorkshireDave VOC Member Last Online: Apr 23rd, 2024 00:30 Join Date: May 2015 Location: Wetherby	My two penneth of experience regarding DEM failure. My issues started with occasional anti skid service warnings. I then noticed fuel consumption had risen & I had no idea why. My next sympton was a 'rumble' similar to an early wheel bearing failure but I had trouble locating it and it wasn't prevalent when turning left or right. Eventually, over some months, more spurious messages appeared and eventually I got the brake failure message along with no tacho, speedo or water temp. I was convinced it was the CEM (based on various tinterweb posts) so I stripped it out only to find it had already been replaced! Whilst it was great news on one level, it also chucked a huge spanner into my thought process 🤔 Having used Lukas' skills at Volvo Diagnostics a couple of years previous, he was the only person I felt I could trust to give me a definitive answer. I know from experience he does not rely entirely on the output from a computer! His advice was simple & incisive. Disconnect the DEM & clear the codes. If the issues disappear, aside from the antiskid warning, them the DEM is the prob. Getting to it & disconnecting it was a challenge. However, the following drive was clear of the break failure warning, the instruments worked again, the gearbox worked & the rumble noise disappeared. I left Wetherby at 04:30 next morning for Tilbury as Lukas said he'd refurb my DEM while I waited. As someone who started working life in electronics and almost ever since been in engineering, the quality of the refurbishment was truly sublime. Even the case was cleaned to a literal 'just out of the mould' standard - truly spotless. It turned out it had the wrong firmware for my vehicle but they sorted that with batting an eyelid! Volvo's price for a replacement & programming was £1200. Lukas' price was £140, which included his freely given priceless advice. Before refitting I was advised to test the pump which I did. Unfortunately I don't think my Haldex has ever been serviced so that'll be done next week with a new filter & oil. I refitted today and, honestly, the difference is night & day. Gear changes are smoother than a babies bum, rumble has disappeared, fuel consumption has improved & no more messages! My journey here was ultimately successful. However it would have been far less painful if we Volvo owners had access to some decent flow charts where simple(ish) tests, such as Lukas suggests, where we could narrow down possible causes. Anyone up for working on some? __________________ 2006 Black XC90 D5 185 Auto Engine change at 162K. all cars everywhere are a perpetual work in progress...